PRESENTER'S GUIDE "USING FIRE EXTINGUISHERS" Part of the "SAFETY MEETING KIT" Series Quality Safety and Health Products, for Today...and Tomorrow
OUTLINE OF MAJOR PROGRAM POINTS The following outline summarizes the major points of information presented in the program. The outline can be used to review the program before conducting a classroom session, as well as in preparing to lead a class discussion about the program. You've probably heard the best way to fight a fire is to prevent it, and that's true. But accidents do happen and fires do start. When this occurs in a workplace, you or a coworker will often be the first to respond, and fire extinguishers become the first line of defense. Fire extinguishers can enable you to act quickly and effectively to protect people and your facility. So you need to understand the equipment, as well as how to use it. Fire extinguishers are designed to put out small fires before they grow out of control. Putting out fires with an extinguisher isn't always easy. It can be hazardous if you go about it in the wrong way. To use an extinguisher effectively it s helpful to know what causes things to burn. Fire always needs three ingredients, fuel, oxygen and heat. The "fuel" is any material that will burn, including: Combustible solids such as wood, paper, cardboard and some metals. Flammable and combustible liquids such as gasoline, toluene and some solvents and cleaning solutions. Ignitable gases such as propane and natural gas. 2
Next, a fire must be in an environment where there is oxygen that it can "breathe". The more oxygen a fire has, the better it will burn. That's why "fanning" a fire makes it flare up. The third element that a fire needs is heat, a "source of ignition" such as a match or an electric spark, that "lights" it and keeps it burning. The best way to put a fire out is to deprive it of oxygen or heat. That is what fire extinguishers do. Though they may look more or less the same, all fires are not alike. The types of materials that are burning and the location of the fire determine how they behave, and how you should put them out. Fire extinguishers work by applying substances that are called "fire retardants". They can cool a fire or deprive it of oxygen (a process known as "smothering") or they can do both. But using the wrong type of retardant on a fire can make a bad situation even worse. For example, an air-pressurized water extinguisher will do a great job of putting out burning cardboard. But using a water extinguisher on burning liquids will only spread the fire further. Since water conducts electricity, you wouldn't want to use it on a fire that is burning in or around electrical equipment, because someone could be electrocuted. To make it easier to distinguish between different types of fires and determine what type of extinguisher should be used on them, fires are divided into "classes". 3
"Class A" fires involve everyday solid combustibles like paper, cardboard and wood. Extinguishers that discharge water, foam and some dry chemical agents can be used on this class of fires. "Class B" fires involve flammable gases, liquids and some plastics. Extinguishers that discharge dry chemicals, foam and carbon dioxide should be used on these. "Class C" fires involve electricity, and can occur in any type of electrical equipment. Extinguishers that apply "nonconductive" substances, such carbon dioxide and dry chemicals, must be used on Class C fires. "Class D" fires involve combustible metals, and are not very common. They can be dangerous to extinguish, so don't try to put out a Class D fire unless you have received training on how to deal with them specifically. The labels on fire extinguishers are always marked with the classes of fires they should be used on. Sometimes they also display "pictographs" that illustrate the classes. Many extinguishers are designed to put out multiple classes of fires. It's important for you to know what types of fires could occur at your facility and what extinguishers you should use to fight them. Talk to your supervisor if you have questions. 4
The fire extinguishers in a facility should be appropriate for the classes of fires that are most likely to occur in the facility. For example, a work area that contains wooden materials, flammable liquids and electrical machinery should be equipped with extinguishers that are rated for Class A, B and C fires. Since many facilities have this combination of substances, multi-purpose dry chemical ABC fire extinguishers are by far the most popular type of extinguisher in use today. These extinguishers use a chemical called monoammonium phosphate that coats the fuel and smothers the fire. But the residue that ABC extinguishers leave behind is not only hard to clean up, it's also mildly corrosive. Dry chemical extinguishers rated for Class B and C fires discharge sodium bicarbonate, also called "baking soda", which is non-corrosive and easy to sweep up. So these extinguishers may be preferable when fighting B and C class fires. The heat from a fire causes the baking soda to release carbon dioxide gas, which smothers the fire. Its residue also forms a barrier between the fuel and oxygen, so that a smothered fire won't reignite. Carbon dioxide (CO2) extinguishers are also rated for Class B and C fires, and they don't leave any residue. They're especially good for use in computer rooms and other areas that contain electronics or other delicate equipment. 5
But while CO2 can smother a fire effectively, it also tends to disperse quickly into the atmosphere. So a blaze that has not been completely extinguished could easily reignite. When using these extinguishers you need to look closely to make sure the fire is out. When a fire needs to be extinguished, our first instinct might be to douse it with water. Water and water-based foams are good at putting out some types of fires, but they can cause serious hazards if they are used on others. While water is a convenient and effective retardant for putting out Class A fires, it cannot be used safely on: Class B fires that involve burning liquids. Class C fires that occur in or near electrical equipment. So most water extinguishers have been replaced by dry chemical "ABC" equipment. But dry chemicals don't work well on some Class A fuels. For example, they can t reach the burning embers that are within a mattress, stack of paper or a pile of sawdust. But water can soak into these materials to extinguish the fire, so water extinguishers still have some uses. Extinguishers that discharge water-based foams are usually rated for Class A and Class B fires, though not for Class C. Foam retardants "blanket" burning materials to cut off their oxygen supply. As a result, foam extinguishers can do a good job of putting out burning liquids. 6
Foam extinguishers can also be applied to spills of flammable liquids to prevent them from catching fire. So foam extinguishers can be especially useful in commercial garages and chemical storage facilities for this reason. There are a number of other types of fire extinguishers that are designed to be used in specific environments, and to put out specific types of fires. Ask your supervisor about what extinguishers are appropriate for your workplace. While it's important to act quickly in a fire emergency, there are several things you should do before you reach for a fire extinguisher. Make sure the fire alarm has been activated (pull it yourself, if necessary). Help other people to start the evacuation process, especially anyone who has been injured. Close nearby doors and windows that could feed the fire with oxygen. A fire that is too large, or has spread into ceilings or walls, may already be too dangerous for you to fight. Smoky fires can be very hazardous as well. Smoke inhalation kills more people than flames. In these cases, you should leave the area and let professional firefighters handle things. If you feel that it s safe to try and combat a fire, grab the nearest extinguisher. Double check its label to make sure it s the right type to use in the situation. Make sure that you have a clear escape route in case you need one. 7
Position yourself within the "effective range" that is marked on the extinguisher's label. For most dry chemical ABC fire extinguishers, this distance will be about 6 to 8 feet. Hold the extinguisher upright. Even under the stress of fighting a fire, you can make sure you use the extinguisher correctly by thinking of the word "PASS". It spells out the four steps you should take. Pull the extinguisher s pin. Aim the nozzle at the base of the fire. Squeeze the trigger. Sweep from side to side with a slow, steady motion. Remember that retardants cool and smother a fire by working on its fuel. So keep the nozzle of the extinguisher pointed at the base of the fire, not the flames. If you are dealing with flammable liquids, be careful not to spread the fire by "splashing" the spill. As the fire gets smaller, step forward to stay within the extinguisher s "effective range". But don't get too close. Be careful where you walk! If fighting the fire is creating a lot of smoke, crouch down near the ground. There will be more fresh air there, and it will be easier for you to see. Most portable dry chemical extinguishers provide about 10 to 15 seconds' worth of continuous spraying. 8
Once the extinguisher is empty: Leave it in an out-of-the-way area so no one will trip over it. Place the extinguisher on its side so others will not try to use it. Leave the danger area, even if the fire appears to have been extinguished. When a building is burning, seconds count, so fire extinguishers should be kept close by where they're easy to find. They also need to be fully charged and functional. OSHA regulations, state ordinances and local fire codes require industrial facilities, offices and public buildings to place portable fire extinguishers near all potential fire hazards. The Department of Transportation requires that all commercial vehicles be equipped with extinguishers, as well. Extinguishers should be mounted on hangers or in marked fire extinguisher cabinets, where they can be clearly seen. Never store an extinguisher on the floor, in a closet, or behind furniture, plants or decorations. When a fire's burning there's no time to have to search for an extinguisher that works. Regular inspections and maintenance of the equipment should be an important part every facility's fire prevention program. 9
Extinguishers should be checked at least once a month to make sure that they are in working order. Any that are located outdoors should be inspected every week. The pressure gauge should indicate that it is fully charged. The locking pin and plastic "tamper seal" should be in place. The hose and horn should be undamaged and unobstructed. All metal parts should be free of corrosion. The service tag on the extinguisher will show when it is due for its next professional inspection. Fire codes require that extinguishers be inspected by an authorized service technician annually, and to have their cylinders pressuretested at regular intervals as well. * * * SUMMARY * * * Fire extinguishers can provide a secure and reliable defense against fires in your workplace. Fires need fuel, oxygen and heat to burn. Take one of these elements away, and you put the fire out. Fires have been organized into "classes" to help you choose the right extinguisher to use. You should know the fire hazards in your workplace, the classes of fires that are likely to occur, and the types of extinguishers you should use on them. When you're fighting a fire with an extinguisher, remember the "P.A.S.S." method: Pull an extinguisher's pin. Aim the nozzle at the base of the fire. Squeeze the trigger. Sweep side to side. 10
Fire extinguishers should be inspected regularly and maintained in good working order. Now that you understand how fire extinguishers work and know how to use them effectively, you can help make your facility a safer place for yourself and your coworkers if a fire ever does occur. 11